Factorise: $6x^2+5x-6$

Factorise: $7x^2-25x-12$

Factorise: $6x^2+7x-3$

Factorise: $1-18y-63y^2$

Factorise: $x\left(12x+7\right)-10$

Factorise: $x^2-\left(1+\sqrt{2}\right)x+\sqrt{2}$

Factorise: $\sqrt{2}{x}^2+7x+5\sqrt{2}$

Factorise $x^2+4x-5$ by using factor theorem.

Factorise $y^2-2y-15$ by using factor theorem.